Shuen Wu

As the proliferation of automation in smart transportation continues, there is a need to secure communication links of “on-the-go” future mobile platforms. In this effort, we implement decoy-state quantum key distribution (QKD), which provides provably secure communication, to mobile platforms such as drones and vehicles. Unlike demonstrations in fiber of fixed point-to-point, QKD between mobile platforms provides unique challenges such as designing systems with reduced size, weight, and power, establishing a stable line-of-sight as the platforms are in motion, and maintaining performance over a wide operating temperature range, etc. We design our QKD transmitter and receiver using a modular design that is platform-agnostic. This allows us to deploy the same QKD system on an octocopter drone and a car without any hardware or software modifications. We describe critical subsystems including our resonant-cavity QKD source, custom prepare and measure optics, pointing, acquisition, and tracking system, single-photon detector, field-programmable gate array-based time-tagger, and qubit-based time-synchronization algorithm. Our achievements include drone-to-drone QKD, drone-to-car quantum transmission, and high-speed (70 mph) vehicle-to-vehicle quantum transmission on a U.S. Interstate Highway.